Rod coupler



United States Patent 3,275,354 ROD COUPLER Wayne N. Sutlilf and Jim L. Downen, both of 2931 Pierce Road, Bakersfield, Calif. Filed June 12, 1964, Ser. No. 374,683 3 Claims. (Cl. 287-103) This invention relates to rod couplers and is particularly useful for coupling together the lower end of a string of sucker rods and the plunger rod of a deep well reciprocating pump. It is an improvement upon the rod coupler disclosed in the pending application of Wayne N. Sutliif, Serial No. 267,573, filed March 25, 1963, now US. Patent No. 3,219,373.

The objects of both of these rod couplers include the following: freedom from end play when coupled; the capacity of being uncoupled at will by subjecting the coupler to torque for a predetermined period of time; the capacity of being self-restored to fully coupled condition whenever said torque is relaxed after being applied less than said predetermined period; the capacity of being uncoupled by less than a single revolution of one of the coupled rods relative to the other, plus means to retard such relative rotation to require the application of torque as aforesaid for said predetermined period of time to accomplish such relative rotation, plus means to reverse said relative rotation thereby restoring the coupler to fully coupled condition, upon the relaxing of said torque before said torque had been so sustained, thereby preventing accidental uncoupling of said rods by transitory torque forces.

The rod coupler of the prior invention above noted was relatively expensive to produce and it is a primary object of the present invention to provide a novel rod coupler which will attain the major objects of said prior rod coupler but yet be much less costly in its production.

The retarding action in both types of rod coupler above discussed is provided by hydraulic dashpots. In the prior rod coupler, the dashpot means has its own self contained body of operating liquid. This is not only a relatively expensive dashpot structure but requires regular servicing of the equipment to be sure each unit contains an adequate supply of operating oil.

It is therefore another object of the present invention to provide a rod coupler embodying a dashpot which is comparatively inexpensive to produce and draws upon the liquid in which the coupler is submerged, under operating conditions, for a supply of dashpot fluid.

The manner of accomplishing the foregoing objects as Well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a vertical elevational view of a preferred embodiment of the invention with the upper or tubular member of the coupler suspended a short distance abovethe lower or pin member of the coupler as these members are related just before uniting or after separating the same.

FIG. 2, drawn in two parts as FIG. 2a and FIG. 2b, is an enlarged vertical section .view of the invention taken on the line 22 of FIG. 1 and illustrating the tubular coupling member lowered so as to bring this slightly into I telescopic relation with the pin member thereof.

FIG. 3 is a view similar to FIG. 2, partially broken away to shorten the same, and shows an advanced stage in the penetration of the tubular member by the pin member of the invention in telescopic relation therewith although just short of a complete penetration which will be necessary to consummate bringing said two members into interlocked relation.

FIG. 4 is a view similar to FIG. 3 and illustrates the consummation of the interlocking of said coupler membars.

FIG. 5 is a fragmentary, vertical, sectional View taken on the line 5-5 of FIG. 3 and illustrates the profile of one of the cams provided on the cam block of the invention and the angle at which this engages the upper end of the pm of the pin member thereof.

FIG. 6 is a cross-sectional view taken on the line 6-6 of FIG. 5 and illustrates the profiles of the blocking bosses on the tubular member and the lugs on the pin member of the invention and how these lugs and bosses may bypass each other and yet be brought into interlocking relation by rotation of the pin in the tubular member of the invention.

Referring specifically to the drawings, the invention is there illustrated as a rod coupler 10 used for connecting the lower end of a sucker rod string 11 and a plunger valve rod 12. The latter rod has a rod coupling 13 secured on its upper end, said coupling having a right-hand threaded receptacle 14 in its upper end, said coupling also having diametrically opposed clutch lugs 15 extending downwardly therefrom. The rod 12 is guided vertically by a rod valve guide 16 which is fixed on the upper end of a deep well pump (not shown) and said rod extends downwardly into said pump to connect with the plunger thereof. Formed diametrically in the upper end of the guide 16 are clutch notches 17 into which the lugs 15 are adapted to fit when the coupling 13 is allowed to drop downwardly onto the guide 16 thus locking the rod coupling 13 against rotation relative to said pump.

The sucker rod string 11 includes a series of inter-connected, individual sucker rods 18 the lower end of the lowermost sucker rod in the string being shown in FIG. 1 as including a sucker rod head 19 having a right-hand threaded pin 20 onto which a special coupling is screwed. This coupling has -a right-hand threaded bore "6 in its lower end.

The coupler 10 comprises a tubular body member 27 and a pin member 28. The tubular member 27 includes a sub 29 having a right-hand threaded pin 30 which screws into the lower bore 26 of the coupling 25. Formed upwardly into the sub 29 is a blind bore 31 which has a relatively long counter bore 32 providing an annular shoulder 33 at its upper end. Formed diametrally in the sub 29 at the upper end of bore 31 is a small diameter bore 34 having counter bores 35, 36 and 37 formed coaxially therewith, counter bore 37 being threaded. The counter bore communicates with the bore 31 and has trapped therein a valve ball 40 and a coiled expansion spring 41, the latter being held compressed against said ball by an orifice plug 42, which is set in place in counter bore 36, by a tubular threaded plug 43 which is screwed into counter bore 37. The plug 42 loosely fits in the counter bore 36 so as to provide a narrow liquid escape passage for liquid from the bore 31, the counter bore 35 and around the plug 42 and out through the tubular screw plug 43. The preferred mode of producing plug 42 so that it will provide such a restricted escape passage is to form each of the opposite ends of the plug slightly oblique with respect to the longitudinal axis of the plug.

Slidable in the counter bore 32 of sub 29 is a plain cylindrical plunger 44 which confines within said counterbore a heavy coiled expansion spring 45 with its upper end pressed against the annular shoulder 33.

Secured to the lower end portion of sub 29 by threads 46 is a cylindrical sleeve 47, a lower portion of which is provided internally with diametrically opposed pairs of bosses 48 the horizontal profiles of which are shown in FIG. 6, while elevational and vertical, sectional views thereof are shown respectively in FIGS. 2b and 5. Fixed at its opposite ends in sleeve 47 so as to extend diametrally therethrough is a cylindrical shaft 49. Formed in an upper end portion of sleeve 47 is a liquid escape passage 50.

The tubularcoupler member 27 also includes a cylindrical cam block 55 which is bifurcated by a vertical diametral slot 56 for slidably receiving the shaft 49, said slot terminating at its lower end in oppositely flaring faces 57. A pair of cams 58 extend downwardly from' the outer edges of the bifurcated lower portions of the block 55. These cams have helical cam faces 59 which terminate at their lowermost points in vertical stop faces rod string with the plunger of the pump at the conclusion of the assembly of the sucker rod string.

To effect this purpose, the pin member 28 of the rod coupler is assembled on the pump and introduced into the well with the latter. The tubular body. member 27, carrying the parts enclosed therein, is then connected to the lower end of the lowermost sucker rod of the rod string 11 so that the completion of the assembly of the 60. In the assembly of the tubular member 27 of the rod coupler 10, the block 55 is inserted in the upper end of the sleeve 47 so that the shaft 49 is received in the slot '56, as shown in FIG. 2b, before said sleeve is screwed onto sub 29. Before this is done, the plunger 44 and spring 45 are already inserted into the counter. bore 32 of sub 29 and the screwing together of the sleeve 47 and sub 29 forces the plunger 44 into the counter bore 32 so as to place the spring 45 under substantial compression.

The pin member 28 of the rod coupler 10 includes a pin sub 61 having a right hand threaded pin 62 which screws into the threaded receptacle 14 .of the rod coupling 13, while extending axially upwardly from sub 61 is a pin base 63 and a pin 64. Formed integrally with and extending diametrally from opposite portions of the pin 64 are pairs of lugs 65,66 and 67, the' latter pair being at the upper end of the pin 64 and being substantially longer axially than the lugs 65 and 66. The pin 64 and lugs 67, at their upper ends, are beveled to form symmetrically sloping ridge faces 68 which have the same slope as the faces 57 which is preferably about forty-five degrees.

As shown in FIG. 6 the pairs of lugs 65, 66 and 67 have a horizontal profile permitting these to freely bypass bosses 48 when the pin 64 is aligned with and properly oriented rotationally with the sleeve 47. This allows free insertion of said pin into said sleeve until theridged upper end of pin 64 comes into engagement with the cam faces 59 of the block 55. Further penetration of the sleeve 47 by the pin 64 may be accomplished only by forcing the sub 29 downwardly relative to the pin 64 so as to produce the same effect as'if said pin were forced upwardly into the sleeve 47 so as to lift the block 55 and the plunger 44 against the retarding effect both of the pressure of spring 45 and the resistance produced by the necessity of expelling liquid confined behind the plunger 44 in counter bore 32, past the orifice plug 42 and out through the tubular screw plug 43. When such resistance has been overcome and the pin 64 and pin base 63 have been forced entirely upwardly into the sleeve 47, so that the lower end of the. latter is in contact with the pm sub 61, the pairs of lugs 65 and 66 are located directly opposite the spaces intervening vertically between the three pairsof bosses 48 whereas the upper pair of lugs 67 are disposed opposite the spaces immediately above For simplification of the drawings, the details of the environment Within which the invention is employed in connecting a sucker rod string to the plunger of a deep well pump, are omitted. It is to be understood, however, that the purpose of the invention, in'the use of the same illustrated herein, is to permit the pump (including its plunger) to be introduced into the well suspended from the [lower end of a string of pump tubing, and then, after this has been completed, to assemble the sucker rod string 11 as this is-inserted down the tubing, the invention providing a means for connecting the lower end of the sucker rod string results in the tubular body me-rnber27 of the coupler approaching the pin member 28 thereof approximately as shown in FIG.,1. Any suitable guide means may be provided, if necessary, to assure a coaxial relationship between the tubular body member 27 of the coupler and the pin member 28 thereof so that a further lowering of the sucker, rod string 11 causes the lower end of the cylindrical sleeve 47 to slidably receive the upper end of the pin member 28 as shown in FIG. 2b. After this initialinsertion of the upper extremity of the pin member 28 into the lower end of the tubular member? 27,"the

sucker rod stn'ng llmay be rotated slowly from the top of the well until the two members 27 and 28 become rota-1.

tionally on'entedas shown in FIG. :2b so that further lowering of the sucker rod .string 11 will cause the tubular member 27 to slide downwardly over the pin member 28 until the helical. cam faces 59 of the cams 581ouv the block 55 engage the ridged upper end'of the pin 64 as shown in FIG. 5 which halts downwardmovement of block 55 and plunger 44,and causes further downward movement of the sub 29 to be retarded by the necessity for discharging liquid trapped in the counter bore 32 0utwardly past orifice plug 42 asthis downward movement takes place.

It is not contemplated that any liquid need be placed in counter bore 32 before the tubular member 27 of the rod coupler is securedat the lower end of sucker rod.

string 11 and the latterextended, as it is assembled, into the well.

in that bore will, of course, escape and be replaced by the infiowing oil. Thus, by the time the sucker rod string 11 has been completely assembled and the tubular member 27 of the coupler has reached a position closely above 1 1 the pin member 28,-as shown in FIG; 1, the counterbore 32 will have been completely changed with oil .so that 7 upon the application of the tubular member 27 to thepin member 28, the dashpot embodied in tubular member 27 will function to retard the telescopic movement of the members 27 and 28.

It is, of course, not essential that the surrounding oil in the'well seep into and fill the counter bore 32 with oil 1 before the members 27 and 28 are caused to telescopically interlock asabove described, because the oil is bound to seep through the bypass passage in the dashpot ofthe coupler within the first hour or two after the couplerhas been integrated so that the dashpot of the coupler is there- 'after fully effective to retard theuncoupling of the cour pler, so that temporary inadvertent applications of torque to the sucker. rod string 11 are ineflective to bring about a separation of the members 27 and 28 of therodcoupler 10. V

The embracing relationship of the cam block 55 and the upper end of the pin member 28 which'takes place upon the integration of the members 27 and 28 is clearly shown in FIG. 4. The helical cam faces 59, applying .torque in opposite directions to opposite extremities of the.

ridged upper end of pin 64, as shown in'FIGS.3 and5.

quickly effect a relative rotation between the members 27 and 28 as soon as the latter has been fully extended into the member 271- 'This' ,relative rotation .is only throughan angle of ninety degrees and terminates with the upper end of the pin embraced by the faces 57 of block 55 as shown in FIG. 4 and with the vertical stop faces 60 juxtaposed close to vertical faces of lug 67 so as I It is anticipated that as soon as the member 1 27 becomes submerged in a body of oil in the well in i which it is to operate,'this oil will start to leak past the plug 42 and into the bore 37 ofithe sub 29, and the air to prevent leftward rotation past this particular point, of the tubular member 27 relative to the pin member 28.

Disconnection of the rod coupler is accomplished by applying a right hand torque to the sucker rod string 11 so that the helical cam faces 59 on the block 55 are caused to ride on the sloping faces 68 on the upper end of pin 64 so as to gradually rotate the sleeve 47 relative to the pin 64 while at the same time raising the block 55 and plunger 44. The dashpot of the device retards this rotation so that the latter may not be performed in less than a predetermined period of time which is selected so that it is longer than it is practically possible for a torque to be inadvertently applied to the sucker rod string 11 which would otherwise be able to uneouple the rod coupler 10.

It is to be noted that whenever the sucker ro-d string 11 is released from the application thereto of right-hand torque so that it is free to rotate to the left, the plunger 44 is pushed downwardly in the counter bore 32. by the spring 45 at a relatively rapid rate so as to create a suction in said counter bore thereby opening the valve 40 and allowing the vacuum in the counter bore to be filled by a fresh supply 'of oil from the body of oil surrounding the coupler 10. The spring 41 is of course sufficiently weak that this oflFers relatively small resistance to the ingress of oil past ball 40 into the counter bore 32 so that the torque created by the expansive power of the heavy coiled spring 45 is applicable to swiftly re-orient the members 27 and 28 rotationally and return these to fully interlocked condition as shown in FIG. 4, immediately upon the sucker rod string 11 being released from any torque which has partially disturbed that relationship.

While only one preferred form of the invention has been disclosed herein, it is to be understood that this has been for illustrative purposes only and that various changes and modifications may be made in this without departing from the spirit of the invention or the scope of the appended claims.

The claims are:

1. In a rod coupler, the combination of: a tubular coupling member; a pin coupling member; interlocking means on said members which slidably admits said pin member into said tubular member, when the two members are aligned, and prevents relative rotation between said members until said pin member has been inserted a predetermined distance into said tubular member, whereupon said relative rotation is permitted by said means and results in said means interlocking said members against separation axially; compressible torque producing means provided Within said tubular member and engageable by said pin member during said relative axial movement between said members to compress said torque producing means, said means then functioning to produce relative rotation between said members thus causing said interlocking means to couple said members together, said torque producing means also resisting reverse relative rotation between said members after said members are thus interlocked, thereby retaining said members in coupled relation; liquid dashpot means including at least one port extending through the wall of said tubular coupling memher and, the retarding action of which is applied to reinforce the resistance by said torque producing means to said reverse relative rotation between said members, said dashpot means drawing its operating liquid directly from that liquid in which said rod coupler is submerged; and means operatively disposed in said port to control the flow of said liquid therethrough.

2. A rod coupler as recited in claim 1 wherein said tubular member comprises a sub having a blind bore e11- tering its lower end said sub also having a liquid inlet check valve and a restricted liquid bypass passage the opposite ends of both of which connect respectively to an upper portion of said bore and to the space outside said member, and wherein said dashp-ot means includes a coiled expansion spring and a piston making a liquid, tight, sliding fit within said bore and compressing said spring therein.

3. A rod coupler as recited in claim 2 wherein said tubular member also includes a cylindrical sleeve secured at its upper end on said sub and extending concentrically downward therefrom, said sleeve having a diametral pin provided therein, said torque producing means including said spring and piston and a vertically, diametrically slotted cam block slidable axially in said sleeve in splined relation with said diametral pin and having helical cam faces on its lower end which are pressed into yieldable engagement with said pin member by said spring, said interlocking means including b'osses formed internally from opposite areas of a lower portion of said sleeve, and lugs formed externally from opposite areas of said pin member for bypassing said bosses when disaligned with the latter and interlocking therewith when said pin member is rotated by said torque producing means after its having been inserted in said tubular member.

References Cited by the Examiner UNITED STATES PATENTS 1,892,517 12/1932 Pennington l296 X 2,989,132 6/1961 Downen l75297 3,038,548 6/1962 Brown l75--296 3,168,340 2/1965 Howard 287ll9 3,180,433 4/1965 Mason -296 X 3,219,373 11/1965 Sutliff 287103 CARL W. TOMLIN, Primary Examiner.

G. A. MILWICK, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noe 3,275,354 September 27, 1966 Wayne N. Sutliff et alo It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, lines 6 to 8, strike out "including at least one port extending through the wall of said tubular coupling member and, "3 line 11, after "means" least one port extending through the wall of said tubular coupling member and "I,

Signed and sealed this 29th day of August 1967,

( L) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. IN A ROD COUPLER, THE COMBINATION OF: A TUBULAR COUPLING MEMBER; A PIN COUPLING MEMBER; INTERLOCKING MEANS ON SAID MEMBERS WHICH SLIDABLY ADMITS SAID PIN MEMBER INTO SAID TUBULAR MEMBER, WHEN THE TWO MEMBERS ARE ALIGNED, AND PREVENTS RELATIVE ROTATION BETWEEN SAID MEMBERS UNTIL SAID PIN MEMBERS HAS BEEN INSERTED A PREDETERMINED DISTANCE INTO SAID TUBULAR MEMBER, WHEREUPON SAID RELATIVE ROTATION IS PERMITTED BY SAID MEANS AND RESULTS IN SAID MEANS INTERLOCKING SAID MEMBER AGAINST SEPARATION AXIALLY; COMPRESSIBLE TORQUE PRODUCING MEANS PROVIDED WITHIN SAID TUBULAR MEMBER AND ENGAGEABLE BY SAID PIN MEMBER DURING AND RELATIVE AXIAL MOVEMENT BETWEEN SAID MEMBERS TO COMPRESS SAID TORQUE PRODUCING MEANS, SAID MEANS THEN FUNCTIONING TO PRODUCE RELATIVE ROTATION BETWEEN SAID MEMBERS THUS CAUSING SAID INTERLOCKING MEANS TO COUPLE SAID MEMBERS TOGETHER, SAID TORQUE PRODUCING MEANS ALSO RESISTING REVERSE RELATIVE ROTATION BE- 